1. Field of the Invention
The present invention relates to a method for measuring the height, and more particularly to a method for measuring the height of a product having multiple components based on laser ranging technology.
2. Description of the Prior Art
The laser ranging technology is a ranging technology by using a laser as a source. The basic principle thereof is that a distance between a laser ranger and an object under test can be calculated according to the time interval between the emission and reception of the laser light, which is emitted out of the laser ranger, then reflected by the object under test and finally received by the laser ranger. The ranging formula is: D=0.5 cxt, where D represents the distance between the laser ranger and the object under test, c represents the velocity of light, and t represents the time interval between the emission and reception of the laser light.
The laser ranging is not only widely used as a ranging technology, but also widely used as a test means in the industry test. For example, it can be used to measure the height of the product or the thickness between two opposite surfaces of the product for testing whether the size of the product accords with the product specification on the basis of the laser ranging principle. When measuring the height or the thickness of the object by the laser ranging principle, it needs to respectively measure the distances from the laser ranger to two surfaces of the object, and then calculates the difference between the distances from the laser ranger to two surfaces of the object, so that obtaining the test result of the height or the thickness of the object.
In the actual manufacture, when determining whether the product's size accords with the specification by means of the laser ranging, the laser ranger may measure the height of a single product, and also may measure the height of a product having multi-components with the different heights. In the prior art, when one product under test has multiple components under test, usually the tester will select a point under test on the surface of each component for going to test. As shown in FIG. 1, when measuring the height of each point of the product having the multiple components, the laser ranger generally needs a pause. Namely, when the laser ranger arrives at one point, and then pauses to measure the height of the one point. After this one point is measured, the laser ranger then moves on next point for ready to measure. It can be seen from FIG. 1 that each point shown in FIG. 1 is a pause-for-measure point 10. This measurement mode is not only easy to result in the misjudgment or the undetected error, but also largely wastes the time because of needing to determine the position of the points under test and to start and stop the laser ranger. Particularly, if the number of the points under test is large or a great deal of the products needs to be tested, this testing mode is time-consuming and laborious.